Engine rebuilding-help me decide

Ok, I'll try to keep the description short, but its a long story.

I have a 73 Impala station wagon. I bought it this spring with 58k original miles on a 454. It had been sitting for 7 years and the owner got it running for me without priming the oil first. So, at about 60k the cam lost a few lobes. To minimize downtime I bought a 454 longblock as well as a comp cam, edlebrock intake, valve springs, lifters, etc. I built the "new" 454 and swapped them out.

The "new" 454 was from a machine shop locally. It was originally purchased by a guy who shortly afterward got transferred to the UK for work and he sold it to me still in shrink wrap. The good news is I got a good deal on it. The bad news is that since I bought it secondhand, I have no warranty.

So, with the "new" 454 in the wagon, I broke in the cam at fist idle for 20 minutes then drained the oil and changed the filter. Took it for a light 100-mile trip and it lost most of its oil pressure. So I drained the oil and it looked like metallic paint. Turns out the rebuilders used not only the wrong pushrods, but they were mix and match pushrods from mopar applications, BBC applications and one from something unidentified. The non-hardened rods shredded on the guideplates and must have destroyed the bearings. There were little piles of fine metal dust at the base of the rocker studs. I cleaned it up as much as possible, replaced the pushrods, and flushed with clean oil several times. It runs fine, but at hot idle it only makes about 5 psi.

So here are my options as I see them, but I'm on the fence and can't decide.

1) Pull the performance parts off the "new" 454 and install them on the 60k original 454

2) Reman the original 454 using the performance parts in the assembly

3) Pull the bearings out of the "new" 454 and replace them and run it risking the shavings in all the nooks and crannies.

Despite having much experience with "building" engines, I've never attempted a lower end. I usually have the machine shop assemble the rotating assembly and then I do cam and heads. I'm willing to do it, but my toolkit lacks the good calipers and precision measuring that might be required.

Any opinions from other builders?

Excellent questions here.
First off, I am always suspicious of some one elses engine building.
I have learned the hard way that if one wants it done right, do it yourself. Roughly about half of all the "professionaly built" engines I have seen done by speed shops etc have serious deficiencies.

1. I sent a 350 Chev for a stock rebuild at a performance shop. After installing it in a 3/4 ton 4x4 pick up, the initial start up produced a very loud banging sound. I pulled a head and found that a tiny chunk of a 1/8 inch drill bit was in the cylinder. Although the engine ran for about 20 sec, the piece of bit was big enough to get squeezed between the piston and the squish band of the head and scored the piston and cyl walls. Sure the engine builder sent another engine but my time lost to re and re the engine made the experience miserable.

2. I had a shop rebuild a chevy 2.8 V6 with an Edelbrock cam and Fiero spec heads. The builder put the wrong rear main seal in there, creating an Exxon Valdez class leak. Also the #1 piston pin was installed incorrectly. The piston pin had scored the pin bore, so it would not rotate freely. The excess friction overheated the piston and allowed too much expansion. The piston scuffed the skirt, which then collapsed, causing a knock you could hear across the street. That engine WAS under warranty and I argued 'till I was blue in the face that the piston was slapping. The engine builder insisted it was just valve lash and refused to honour the warranty. I had to fix it myself.

3. A friend bought a 350 Chevy to go in my old hot- rod short box chevy van that I sold him. He bought it from a high school shop class where they changed over to EFI Civics instead if 30 year old Chevys.
This engine was brand new - never used, but it had been disassembled and reassembled about 10,000 times by 14 year olds.
Anyways, I told him to go through it with a fine tothed comb and check everything. He didn't.....and the engine lasted 6 weeks, before all the main bearing caps fell out. It turns out all the cap bolts were stretched about 1/2 inch longer than they should have been, thanks to 10,000 sessions of over torquing.

Okay, I have lots more horror stories, enough of my past. Your engine.........

If you used a good oil filter, the intrusion of particles should be minimal.
Engine and cam bearings are really soft. The foreign particles will embed themselves in the soft bearing shell and likely will not score the journals.
I have seen metal shavings and cuttings left over from machine tools work theur way through oil passages and cut up bearing shells badly, while leaving the journals looking perfect.

I would suggest to go through the new 454 and fully asses the damage.
Of course you might find other things in the engine are a mess. Be sure that other things, like the head and piston combination is not mis-matched, and the crank isn't warped or twisted. It might be an idea to check the ring end gap and the wear. If the builder used odd push rods, who knows what other parts he recycled.

Still, its probably better to use a new engine rather than pistons/rings with 60k on them. So if the 'new' engine checks out, them repair it.

Of course, count on replacing all the main and rod bearing shells, and cam bearings.
Unless the journals have big nicks on them, (unlikely) they can be polished by hand with a light touch with some fine emery cloth. If the bearings feel mirror smooth to the touch, leave them alone.

Calipers are not necessary to get a good measurement of the crank journals. Use Plasticgauge. It comes in 3 sizes, depending on the desired clearance. I have found its quite accurate down to.01 inch.

If you can, pull out a couple of plugs for the oil galleries and chase the bores (and the whole engine) with lots of soapy water and bottle brushes.

Check the clearance on the oil pump gears, or just count on installing a new one. If you find the bearing clearances are a bit on the loose side, (the machine shop might have done that deliberatly) go for a high volume (not high pressure) pump.

I hate to sound cruel but here goes and it's the only way you'll end up with something worth a shit.
Remove the engine now.
Install the other engine and use it till you do the following:
Disasemble the crapped motor and have the block boiled, then clean ALL OIL passages with a block cleaning kit.
Install new mains and inserts. When you get the bearings ask for some plasta gage to check the clearence on the bearings.
Check the cam bearings, clean the lifters, oil pump.
After everything is clean check every part and whats good use, and any doubt chuck and replace.
Do this and if you do it right you should have a good mill till when-everr.

Albert

If your quite comfortable rebuilding heads and the rest of the top end then doing a bottom end will be no trouble at all.
At the end you will wonder what all the fuss was about.
Iv always thought the top end involved far more fuss, and Iv usualy left the head to the experts to put together.
But Iv worked on bottom ends on engines that are still mounted in a car (on a hoist, lower subframe, remove sump, pull bearings till you find a bad one).

And of course it sounds like the only way you can be certian the job gets done right is going to be to do it yourself, and to do it properly.
And that means pulling the engine apart and cleaning out all the oil ways.

Ok, so how does this sound? Tear the new one down, clean it, and reassemble it with new parts. Should I just buy a set of cleaning brushes and do it with a hose and some dish detergent? Or should I hot tank it? Other than bearings and oil pump, what else should be done; rings? or should I just pull the pistons and rings together, then put them back in their same bores?

Since the machine work is not trusted, what specifically should I check? I know to check ring end gap, deck flatness, bore size, taper, and out-of-round, and journal size to make sure of what bearings to get. Anything else to check while its apart? If they used crappy pushrods, maybe they used bad con rods? What should be checked?

I know I'll need some new tools, like a bore measuring tool, a ring compressor, a ring installation tool, etc. Can you think of anything else I'll need?

Hot tanking it will destroy all non ferrous metals (bearings, bronze valve guides, paint etc) and is not necessary.......unless the previous builder never hot tanked it either. Its only required to remove years of sludge and carbon. Besides, it will not remove all debris from the oil passages anyways. You would still have to clean out all the passages.

I would say to disassemble the "new" engine, inspect everything, and then reasses the best route to go.

Those items that you can check are a good start. A close examination of any wear patterns on the piston and bearings will tell you a lot. If there is anything badly wrong, it will show up even though the engine has only been run for a short while.
Check the rods for free wrist pin movement and for twisting. If they are badly twisted they will have already scuffed the pistons.
If the pistons look okay and the clearances check out fine, reuse them. Likely the previous builder actually got a set of new pistons and rings - they're a lot cheaper that way.

Of course if he just re-ringed an old engine..........then you have to decide which engine has less wear.

As for additional parts, have a look at new head and main cap bolts and rod nuts and bolts, especially if the old ones are too long (stretched bolts) or look bad.

Do you have a good torque wrench (clicker or round dial type....not the cheapie chrome pointer type.)

Yup. Its a craftsman clicker and it maybe should be recalibrated before a project this important. It has torqued a lot of lug nuts and heads in its short life.

I'm glad you're around. That's all stuff I didn't think of. Should I use torque on the rod bolts or invest in a stretch gauge?

Yup. Its a craftsman clicker and it maybe should be recalibrated before a project this important. It has torqued a lot of lug nuts and heads in its short life.

I'm glad you're around. That's all stuff I didn't think of. Should I use torque on the rod bolts or invest in a stretch gauge?

Depends on what rod bolts your using or what the Mfg. states. I use ARP bolts and use the stretch method.

You've got a million dollars worth of support here, and if you don't get in a hurry the first time, and when all else fails ask for help, you'll do OK and end up with a good engine. I know their's lots of good engine builders out there, but I personally only know of a few I would trust, and for every good one, maybe 100 wanna-be's. You have some good advice on this thread, take a deep breath, roll-up your sleeves and go for it.
You have PM and eMails so use them.

Mr. MagicRat, I think maybe it would be safer being who knows what they did and didn't do to go the whole ball of wax. Better safe then sorry. What do you think? For the few bucks better doing it totally right even if it takes alittle longer than skimp.

Albert

Mr. MagicRat, I think maybe it would be safer being who knows what they did and didn't do to go the whole ball of wax. Better safe then sorry. What do you think? For the few bucks better doing it totally right even if it takes alittle longer than skimp.

I would agree. This is a good example of someone's "rebuild" might be worse than getting an original, untouched greasy lump of an engine.

If money is not a huge concern, you are correct......all parts should accuratly checked and measured, with anything suspect being tossed.
Also, a new pump, new bearings, all new fasteners, new rings and a cylinder honing should be done, even if all the other parts check out, just to be safe.

Just a horror story to add. A while ago under the videos section I actually posted a video of my friend Tim in his dakota truck. He had a shop in florida who are supposedly 'experts' in making and designing supercharged mopars (he has a supercharged 408ci). About a month into having the motor (and babying the living crap out of it, only taking it to the track once) he started losing oil pressure. Finally he couldn't get over 35 even at 5k rpm. (General rule of thumb is 10psi per 1k RPM) So he took apart the motor, Two of the main cap bolts had walked out allowing for the crankshaft to walk back and forth. (and destroying all main bearings in the process). Only explanation we could possibly find is that those bolts weren't torqued down. I have NEVER heard of this happening on any other vehicle. Company wouldn't even send parts to fix it let alone do the service. Their exact words "Were in a company to make business, not to solve your problems." Kinda shitty when you drop 11k on a motor.

My recommendation curtis. Tear the motor apart and do it right. Have all the parts magnafluxed and have the block hot tanked. Replace all the bearings and have everything balanced. If your crank journals are scratched they can always be cut down. Check for the condition of your pistons as well. After you get it all back, before putting it together, give it all a soapy bath to get the machining oil and any stray metal shavings off. Followed by a spray down with WD-40 to prevent any rusting. Sorry but I'm just really anal about the assembling bottom ends. But who knows if/when you do the tear down, you can always go and upgrade things to like hyperutectic or forged pistons and may be a more aggressive cam :) best of luck, let us know how goes!

Two of the main cap bolts had walked out allowing for the crankshaft to walk back and forth. (and destroying all main bearings in the process). Only explanation we could possibly find is that those bolts weren't torqued down. I have NEVER heard of this happening on any other vehicle.
Interesting story!! Wow, 11k.......I could never spend that much on a motor unless it was going to make me a living.

BTW you may have checked my long post, above. My buddy's SBC did the same thing. Sometimes overtightening bolts can have the same result, they stretch beyond their yeild point and are weakened. If they don't snap, they can back off and fall out.

Frankly, for 11k they should have drilled the bolts and wired everything down or used fold-over washers. Even my 1949 Ferguson tractor had that feature.

Yeah, sorry I did read it, its whats sparked my reply, sorry, durr. So over torqueing them could have done it? Thats interesting... Do you lose any of the strength on the bolts when you safety wire them like you suggested? Now that I think about it, aren't those bolts hardened? good luck drilling through those...

Well, thanks to all of your recomendations, I've decided the following:

I'm going to completely disassemble both engines down to every nut and bolt. I have ARP rod and main bolts, all new fel pro gaskets, a new high-volume Melling pump, and a few other goodies. Of course I have to wait on bearings until I measure the journals, but I'm pretty set on parts to make one engine out of these two. I bought some micrometers, a dial indicator, and I already have some good vernier calipers, so I will measure everything meticulously. I'll take the best of what I have and re-machine anything that might need it and make one good engine. My guess is the "new" block will be better than the old one, and I already know the "new" crank is not the greatest since I noticed the front snout threads were partly stripped. I'll most likely use some 049 heads I have on the shelf that I know are straight and have a good 3-angle valve job.

Then I'll probably take the remaining parts, re-machine what I need, assemble it with the factory intake and a factory regrind cam and sell it on Ebay.

Thanks Soooooo much for the helps folks. Keep it coming if you think of anything else.

Sounds like you've got the plan bro. If you do that you'll end up with a strong engine (ARP) and sleep good at night knowing it done right.